Can you jack up a cottage and build a slab on grade underneath it?

William Rae
Updated: June 10, 2021

I have a cottage in Quebec which used to be resting on the ground. In the 1950s they dug under neath and poured concrete and used cement blocks to make a three quarter basement. It is wet in the spring and damp throughout the summer making the bungalow humid in all seasons. THis mostly due to the house being directly next to a hill.

I've looked at your radiant air heating solution and was wondering if it would be possible to raise the house 2-3 feet and put it on gravel and an insulated slab while turning the basement into a thermal battery by filling it with sand and running piples through it. If so, can you recommend any companies who would be up to the task?

Responses (3)

William Rae 3 years ago

Thanks for your response and the link to get a quote. Yes, I understood that the house has to be much higher during the construction phase. I've seen many houses propped up like this in Constance Bay when being repaired after flooding. Perhaps I didn't phrase the question well. The objective, after the rebuild, is that the house will rest 2-3 feet higher than it was prior to putting slab on grade in place. What you didn't answer was whether it is economically viable to convert the old basement into a thermal battery. Perhaps this is not your area of expertise so I shall seek the answer elsewhere. Thanks again.

Mike Reynolds 3 years ago

If you raise your cottage and put an insulated slab underneath and drop it down on top, the concrete of that slab becomes the thermal battery. For something to act as thermal mass and store heat, it needs to be separated thermally from the ground. Unless you plan to insulate underneath the sand then it wouldn't benefit you.